Acoustic dampening materials are presently used by many vehicle manufacturers to address NVH (noise, vibration and harshness) concerns in vehicles. The dampening material can be a foam installed inside a hollow cavity defined within the vehicle body. Sometimes such foam (e.g., acoustic spray foam) is injected into the hollow cavity within the vehicle body. When injecting the spray foam, many vehicle manufacturers do not attempt to contain the injected foam within the cavity body but rather allow it to be free flowing.